fix(ci): ensure CMake >= 3.5 is installed for lnd_grpc_rust tests

Add a step to the CI workflow to check and install CMake if it’s missing or below version 3.5.
This fixes the build failure in the LND integration tests caused by prost-build v0.10.4,
which requires CMake >= 3.5. Since ubuntu-latest is not a fixed version, this ensures
compatibility with potential future changes in the runner environment.

Closes lightningdevkit#515

Author: moisesPompilio

.github/workflows/lnd-integration.yml

@@ -9,6 +9,24 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
 
+      - name: Verify CMake version
+        run: cmake --version
+
+      - name: Check and install CMake if needed
+        # lnd_grpc_rust (via prost-build v0.10.4) requires CMake >= 3.5 but is incompatible with CMake >= 4.0.
+        # This step checks if CMake is missing, below 3.5, or 4.0 or higher, and installs CMake 3.31.5 if needed,
+        # ensuring compatibility with prost-build in ubuntu-latest.
+        run: |
+          if ! command -v cmake &> /dev/null ||
+             [ "$(cmake --version | head -n1 | cut -d' ' -f3)" \< "3.5" ] ||
+             [ "$(cmake --version | head -n1 | cut -d' ' -f3)" \> "4.0" ]; then
+            sudo apt-get update
+            sudo apt-get remove -y cmake
+            wget https://github.com/Kitware/CMake/releases/download/v3.31.5/cmake-3.31.5-Linux-x86_64.sh
+            chmod +x cmake-3.31.5-Linux-x86_64.sh
+            sudo ./cmake-3.31.5-Linux-x86_64.sh --prefix=/usr/local --skip-license
+          fi
+
       - name: Create temporary directory for LND data
         id: create-temp-dir
         run: echo "LND_DATA_DIR=$(mktemp -d)" >> $GITHUB_ENV